Category Archives: Architecture

Evangelizing

A while back I got into a discussion with another developer. The other guy basically critiqued my code because Angular 1 was so much better than Knockout. It really annoyed me, not because I felt the other person was wrong, or at least not wrong in the sense that I loved Knockout that much. But it annoyed me because its really comparing apples and pears. Sure, both targeting to solve workloads for frontend development on the Web. The arguments presented was very clearly for Angulars ease and against Knockouts idiotic properties being “ko.observable*”. But fundamentally they are different in its underlying core values and concepts. Knockout aiming for a reactive model with its observables, while Angular not having any reactive model at all and being a MVA (Model View Anything) – not opinionated.

This is what bugs the hell out of me. Since these things are so different, fundamentally – how can one be better than the other? And as a consequence, just because one has found something that makes sense for you, why does it have to be true for everyone else? To me for instance; Angular is just completely weird and can’t understand why one would like it at all.

Lets take a step back; this is not a “Foo Framework” against “Bar Framework”. I’m trying to get to the core of something that I think is way much broader than just software development – but probably more visible in software, seing we have all the options we have. Going back to when I grew up for instance, I was a fan of SONY’s HiFi equipment, while one of my best friends was a JVC fan. We had the weirdest discussions. Enter my third friend who was fan of things no one had ever heard of; NAD, Denon and similar. The discussions got even weirder – not from our third friend, but from the others trying to convince him that he was wrong. You can see this with just about everything – people being so convinced their choice of car is the best, TV and of course religion. It seems that this is part of human nature. And we love to evangelize it and try to convince everyone else we’re right.

Trust me, I’m not taking a high road here; because I do this myself. I find something that I enjoy enough to start “evangelizing” it. This is probably something well defined in psychology already; related to wanting to getting a reinforcement of ones own beliefs and decisions.


Core values

<>There is nothing wrong with a good discussion and if you’ve discovered something you should of course show it off and see if others find it cool. But if you’re in a team, having these discussions around one thing being better than other can truly be poison. In my oppinion it also reflects a symptom of lack of common core values. The discussion of Angular vs Knockout as described above is a weird one because it really is not about a discussion between the two, but rather about the differences in underlying mindset and core values. If you’re used to and enjoy a particular way of thinking, changing to something else is very hard. For instance, if you’re used to object oriented programming, functional can be too far away to understand.

Job protection

<>A scary thing I’ve seen a few times; people get comfortable in their job – so comfortable that they start making up reasons for keeping their beloved way of doing things. The reasons behind this is not always obvious. The ones I’ve encountered have been in two categories.

  1. I’ve spent a lot of time learning what I know now and don’t see the point of learning anything new.
  2. The company has had success with the way we’ve done things.

<>For the first reason I’m just going to say “ehh… what…”. That is especially true for our line of work; software development. A relatively young business with so many things changing all the time, and not only changes in software – but the hardware in which the software is running on. Personally I think that is a risky way of going about thinking in our line of business.<>The second reason; if you’re having success it is really hard to see and even argue that you should change your way. If the business you’re working for is having success, but for instance the software you’re working on hits a snag and you get to the point of getting to rewrite it. Even then, you will have a hard time seeing that you need to do it in a different way; after all – the way you did it worked, because it brought success.

In both cases I think the boiling frog anecdote might be the reason behind. Basically, while building something over time – you won’t notice the things that lead to something not really being done in a good way. You’re having many small successes and feel good periods and you simply aren’t noticing that the project is in fact failing. Most projects do tend to have the best velocity in the beginning and slow down over time. Something the team members executing on it won’t notice, because it is happening slowly. But anyone external to the development team is noticing, because their demands for new things have not declined over time but rather increased and often these are the people dealing with the problems as well – while the development team is having a hard time getting through things at the right pace.

I find what Einstein saying: “Insanity: doing the same thing over and over again and expecting different results. interesting and so true. One gets into discussions with management of needing to recreate the product from scratch, because you’ve identified something that is holding the development back and is too painful to fix. You get to do “File -> New Project” and do it again using the same kind of thinking we used when we created the problems in the first place (referring to another Einstein quote).

<>We are so lucky in our profession; there are so many choices – so many ways of doing things. It truly is a luxury.

Mixing it up

<>At a place I was we were about to embark on a rewrite. A few of us had discovered some new principles and experienced some pain while doing a small 3-4 month project in isolation. From this two of us were tasked to do a small proof of concept for the larger project, to sketch out a direction and a starting point for a discussion. After doing this we decided on the direction for the project and what fundamentals to go for. To get the team familiar with different thinking, we mixed things up a bit by doing a period of Ruby development. Writing Ruby and discovering the culture of rubyists let us write our C# in a different way when we got back to it.

Keeping fresh

<>So, how do you keep fresh thinking? It is hard, it really is. Everyone suggesting everything from kode katas, pair programming, friday lightning talks and all these cool things must realize that it is hard to get there. They are all good ideas and things that can help your team keep fresh. But getting to a place where you can build this type of culture is hard. You need the trust from the business to be able to do so. Also, you probably need to have a certain critical mass of people working together before it can be accomplished. Lets face it, being a development team of one makes this very hard. But it is very doable. It starts with recognizing that one has to keep fresh and on top of things. If you think when you graduated that you didn’t need to learn new things, you need to start with changing your attitude. That attitude won’t push anything forward in terms of new ways of doing things. Innovation comes from being aware of what is going around out there and combining wizdom and build on top of it or go in a different direction from established wizdom – but nevertheless, its about knowledge.

Breaking it all up…

One way of being able to push forward and try different things to be able to learn new tricks and gain knowledge could be to start breaking your software up into smaller pieces; enter the buzz of the Micro Services. Sure, there is a lot of buzz around this. But cut to the bone; its about breaking monoliths up into smaller digestable pieces. These digestables could be implemented in different ways, in fact – I would argue they should be. Basically because the different parts have different requirements both for business and ultimately also technical. This is a great opportunity to mix things up.

Back to the value thing…

Remember I said something about core values. I’m convinced this sits at the heart of it. If you get to work and it is a predictable environment in terms of you know you share something with your coworkers. Having the thing you share being core values, rather than the belief in something hard and concrete as a specific technology – you move the discussions to a more healthy level. If your discussion is which of Windows, Linux or OS X is the best operating system, you’re probably not solving the real problems. If you can look past this and past implementational details and start having a solid fundamental that you all believe in – you can move up the stack much more rapidly. Chances are that a lot of the decisions will automatically be made for you if you settle the core value debate first. I’ve blogged about this before – I have no problem reiterating the importance of this, I think it is at the heart of a lot of silly discussions that could’ve been resolved without them having started.

Wrapping up…

<>Is it really important that I drive a Toyota and you drive a Ford? Will the world be a better place if I switched to a Ford? Probably not! Conformity is nothing but just that. It doesn’t really solve any fundamental issues, it covers it up. It is the fundamentals that are different. In software development, these fundamentals are core principles – how you believe software should be written and what makes you productive. This view is a subjective view and it is also a very temporary view. Once you’ve learned new ways of doing things, chances are you look back at your previous knowledge level and laugh or you’re embarressed you ever had that view. If you’re really cool, you even move forward in life and forget you had the view and laugh at people who have the view you had way back… ehh… a whole month ago… Everything is hard until you know it, and then it is the easiest thing in the world. We tend to make a point about it as well. Once we know it, we’re so proud of knowing it that we tell everyone. Knowledge is a moving target, new knowledge emerges – embrace this concept and embrace change. I know I will work for this and aim for getting better at doing better in this area. I have a few comfort zones to break out of and will push forward. Wish me luck!


Concepts and more

With Bifrost we’re aligning ourselves more and more with being a platform for doing Domain Driven Design. Introducing more and more artefacts from the building blocks as we go along. When we set out to build Bifrost, we decided early on to be true to not be building anything into it that we didn’t need in a real world scenario. This was after we had started falling into the pattern of what if of software development. We started imagining problems and had to deal with them way before they had actually happened. With the risk of generalising; a fairly common scenario amongst dirty minded tech people. It stems from experience, knowing that there will always be something that can go wrong. Sure, there always is. I digress, I think this could probably be a blogpost on its own. The point being, we were heading down this path and for some reason got jolted back to reality and we started focusing on implementing only the things we needed and rather actually go back and remove things that came out of the “what if game”. On this new path we wanted to also stay focused on implementing things that were aligned with DDD and keep a close eye on the user.

Concepts

With the philosophy of CQRS at heart built with SOLID care we keep a very close eye on being very specific in our modelling. Things that are used in one part of the system is not automatically reused somewhere else, for the DRYness. We don’t believe in DRYing up properties and we favor composition of inheritance. Logic is still kept only once, on the command side of the fence. With all these principles at hand we were missing something that would link it all back together and make things look and feel consistent.

Let’s look at a scenario; say I want to update the address of a person. A command could be something like the following:

using System;
using Bifrost.Commands;

public class UpdateAddressForPerson : Command
{
   public Guid PersonId { get; set; }
   public string Street { get; set; }
   public string City { get; set; }
   public string PostalCode { get; set; }
   public string Country { get; set; }
}

In Bifrost you’d then have a CommandHandler to deal with this and then an AggregateRoot that would probably look like the following:

using System;
using Bifrost.Domain;

public class Person : AggregateRoot
{
   public Person(Guid personId) : base(personId) {}
   public UpdateAddress(string street, string city, string postalCode, string country)
   {
      // Apply an event
   }
}

The aggregate would then apply an event that looks like the following:

using System;
using Bifrost.Events;

public class AddressUpdatedForPerson : Event
{
   public Guid PersonId { get; set; }
   public string Street { get; set; }
   public string City { get; set; }
   public string PostalCode { get; set; }
   public string Country { get; set; }
}

An event subscriber would pick this up and update a read model that might look like the following:

using System;
using Bifrost.Read;

public class AddressForPerson : IReadModel
{
   public Guid PersonId { get; set; }
   public string Street { get; set; }
   public string City { get; set; }
   public string PostalCode { get; set; }
   public string Country { get; set; }
}

That was the artefacts we would typically be dealing with; command, aggregateroot, event and readmodel. For simplicity, these look pretty much the same – but they don’t have to, and in fact; most of the time they don’t. Lets address something here. We’re losing out on a potential in the modelling here. Take the Guid representing the unique identifier for the person. This is in fact something  that is part of the domain vocabulary that we’re losing by just making it a Guid directly.

In Bifrost we have something called ConceptAs that we can use to represent this domain concept. This is a base class that we recognize throughout the system and deals with properly during serialisation between the different out of process places it might go.

using System;
using Bifrost.Concepts;

public class Person : ConceptAs<Guid>
{
   public static implicit operator Person(Guid personId)
   {
      return new Person() { Value = personId };
   }
}

What this does is to wrap up the primitive, giving us a type that represent the domain concept. One modelling technique we applied when doing this is to stop referring to it as an id, so we started calling it the noun in which it represented. For us, this actually became the abstract noun. It doesn’t hold any properties for what it represents, only the notion of it. But codewise, this looks very good and readable.

In the ConceptAs base class we have an implicit operator that is capable of converting from the new type to the primitive, unfortunately C# does not allow for the same implicit operator going the other way in the base class, so this has to be explicitly implemented. With these operators we can move back and forth between the primitive and the concept. This comes very handy when dealing with events. We decided to drop the concepts in the events. The reason for this is that versioning becomes very hard when changing a concept, something you could decide to do. It could also make serialization more complex than you’d hope for with some serializers. Our conclusion is that we keep the events very simple and uses primitives, but everywhere else the concept is used.

The way we structure our source we basically have a domain project with our commands, command handlers and aggregates. Then we have a project for our read side and in between these two projects sit a project for holding the domain events. With this model we don’t get a coupling between the domain and the read, which is one of our primary objectives. The concepts on the other hand, they are going to be reused between the two. We therefor always have a concepts project where we keep our concepts.

Our typical project structure:

2015-02-03_07-43-27.png

So, now that we have our first concept, what did it do? It replaced the Guid reference throughout, introducing some clarity in our models. But the benefit we stumbled upon with this; we now have something to do cross cutting concerns with. By having the type of pipelines we have in Bifrost, we can now start doing things based on the type being used in different artefacts. Take the command for instance, we can now introduce input validation or business rules for it that would be applied automatically whenever used. Our support for FluentValidation has a BusinessValidator type that can be used for this:

using Bifrost.FluentValidation;
using FluentValidation;

public class PersonBusinessValidator : BusinessValidator<Person>
{
   public PersonBusinessValidator()
   {
      RuleFor(p => p.Value)
         .Must(… a method/lambda for checking if a person exist …)
         .WithMessage(“The person does not exist”);
   }
}

As long as you don’t create a specific business validator for the command, this would be automatically picked up. But if you were to create a specific validator for the command you could point it to this validator as a rule for the person property.

The exact same thing can then also be used for an input validator, which then would generate the proper metadata for the client and execute the validator on the client before the server.

It opens up for other cross cutting concerns as well, security for instance.

Value Objects

A second type of object, with the same importance in expressing the domain and opening for solving things in a cross cutting manner are value objects. This is a type of object that actually holds information, attributes that have value. They are useless on their own, but often used in the domain and also on the read side. Their uniqueness is based on all the fields in it. We find these in any domain all the time, they are typical things like money, phone number or in our case address. These are just the off the top of my head type of value objects you’d have, but you’ll find these in many forms. Lets tackle address:

using System;
using Bifrost.Concepts;

public class Address : Value
{
   public string Street { get; set; }
   public string City { get; set; }
   public string Postal { get; set; }
   public string Country { get; set; }
}

 

The Value baseclass implements IEquatable and deals with the property comparisons for uniquness.

With the value object you do get the same opportunities as with the concept for input and business validation, and yet another opportunity for dealing with cross cutting concerns.

If we summarize the sample before with these new building blocks, we would get:

using System;
using Bifrost.Commands;

public class UpdateAddressForPerson : Command
{
   public Person Person { get; set; }
   public Address Address { get; set; }
}

Our event:

using System;
using Bifrost.Events;

public class AddressUpdatedForPerson : Event
{
   public Guid PersonId { get; set; }
   public string Street { get; set; }
   public string City { get; set; }
   public string PostalCode { get; set; }
   public string Country { get; set; }
}

As you can see, we keep it as it was, with the properties all in the event.

Our AggregateRoot:

using System;
using Bifrost.Domain;

public class Person : AggregateRoot
{
   public Person(Guid person) : base(person) {}

   public UpdateAddress(Address address)
   {
      Apply(new AddressUpdatedForPerson {
         Person = Id,
         Street = address.Street,
         City = address.City,
         Postal = address.Postal,
         Country = address.Country
      });
   }
}

The readmodel then would be:

using System;
using Bifrost.Read;

public class AddressForPerson : IReadModel
{
   public Person Person { get; set; }
   public Address Address { get; set; }
}

Conclusion

For someone more familiar with traditional N-tier architecture and modelling your EDM or rather than separating things out like this, this probably raises a few eyebrows and questions. I can totally relate to it, before starting the Bifrost journey – I would have completely done the same thing. It seems like a lot of artefacts hanging around here, but every one of these serves a specific purpose and is really focused. Our experience with this is that we model things more explicitly, we reflect what we want in our model much better. Besides, you stop having things in your domain that can be ambiguous, which is the primary objective of DDD. DDD is all about the modelling and how we reach a ubiquitous language, a language that represent the domain, a language we all speak. From this perspective we’ve found domain concepts and value objects to go along with it to be very useful. With them in place as types, we found it very easy to go and retrofit cross cutting concerns we wanted in our solution without having to change any business logic. When you look at whats involved in doing it, its just worth it. The few lines of code representing it will pay back in ten folds of clarity and opportunities.

CQRS applied : a summary

Every now and then in a software career you get a chance to write something from scratch and try out new things; a proper greenfield project. I’ve had that luck a couple of times and latest a project that proved to be the complete game-changer for me personally. Game changer in the sense that I gained a knowledge that I am pretty sure I will treasure for, if not the rest of my career, at least for quite a few years moving forward. The knowledge I am talking about can be linked back to applying CQRS, but it is not CQRS in itself that is the knowledge, its the concepts that tag along with it and the gained knowledge of how one can write code that is maintainable in the long run. Its also about the things we discovered during the project, smart ways to work, smart code we wrote – techniques we applied in order to meet requirements, add the needed business value, and at the same time deliver on time with more than was asked for.  

This is a more in-depth post than the talk I did @ NDC 2011

… from the top …

For the last couple of years, till March this year, I had the pleasure of being hired by Komplett Group, the largest e-commerce in Norway. At first I was assigned tasks to maintain the existing solution and was part of the on-premise team to do just that. As a consultant, that is very often what you find yourself doing – unless you’re hired in to be a particular role, like I’ve been in the past; system architect. I helped establish some basic architectural principles at that time, applying a few principles, like IOC and other parts of our favorite acronym; S.O.L.I.D. I remember feeling a bit at awe of just being there, they had a solution that could pretty much take on any number of clients and still be snappy and they never went down. I’ve learned to respect systems like that, even though it requires a lot of work – not necessarily development work, but a lot of the time IT or DevOps help keep systems alive. Anyhow, after a few months, back in 2009 I was asked by the department manager if I wanted to lead a small team on a particular project, an administration-tool for editing order details. With my background earlier as a team lead and also as a department manager myself, I kinda missed that role a bit and jumped at it. It was to be a stand-alone tool, accessible from the other tools they had, but we were given pretty much carte-blanche when it came to how we did it, whatever technology within the .net space we wanted. We settled on applying ASP.net MVC, Silverlight for some parts, WCF for exposing service for the Silverlight parts and nHibernate at the heart as the ORM for our domain. 

Part of the project was also to try out Scrum, having had quite a bit of experience with everything ranging from eXtreme Programming to MSF Agile and later Scrum, that excited me as well. So we applied it as well. 

Half-way through the project we started having problems, our domain was the one thing we shared with the others and we started running into nightmare after nightmare because we worked under the one-model-to-rule-them all idea. Which is really hard to actually get to work properly, and looking back I realize that most projects I’ve been have suffered from this. We ran into issues were for our purpose we needed some things in *-to-many to be eager fetched, which had consequences we could not anticipate in other systems that was using the same model. But we managed to come up with compromises that both systems could live with – still, we weren’t seeing eureka, just brushing up against the problems that a lot of projects meet without seeing that the approach was wrong. A bit after this we started brushing up against something that really got us excited; Commands. Without really knowing about CQRS at this point, but more coming from working with Silverlight and WPF, the concept of modeling behavior through commands. The reason we needed these commands was that we needed to perform actions on objects over a long period of time; potentially days, and at the end commit the changes. We came up with something we called a CommandChain – a chain of commands that we appended to and persisted. Commands represented behavior and modified state for the most part on entities when executed. We came up with a tool were we could debug these chains, and we could inspect which Command was causing problems and not.

NewImage

All in all, we were quite pleased with the project; we had done a lot of new things, applied TDD in a behavioral style, started exploring new corners of the universe we had yet to realize the extent of. Delivered not too badly on time, not perfectly on time – but close enough.

The turning point

After yet another 6 months or so, there were initial talks about the need to expose functionality from the web-shop to other systems used internally, a few design meetings and meetings with management lead to a new project. The scope of the project turned out to be not only exposing some services, but also a new web-shop frontend targeted and optimized for smartphone devices. The project was initiated from a technical perspective and not one with a specific business need in mind. From a technical perspective, the existing codebase had reached a point were it was hard to maintain and something new needed to replace it to gain back velocity and control over the software. It was to be a complete greenfield project, totally throw things overboard and just basically work with existing database but add flexibility enough that even that could be thrown out the door, if one ever wanted to do that. Early on I was vocal about them needing an architect to be able to deliver this project, I pointed in a couple of directions to internal resources they had – but people pointed back to me and I soon found myself as the system architect for the project. 

Requirements

When dealing with e-commerce at this level, there are quite a few challenges. Lets look at a few numbers; in the product catalog there was at the time I got off the project about 13.000 products, there was an order shipped every 21 seconds, in 2011 that amounted up to 1.454.776 orders, ~30.000 living sessions at any given time. Sure, its not Amazon, but for our neck of the woods its substantial. These numbers are of course on an average, but come busy times like Christmas, these numbers are more focused and the pressure is really on for that period in particular.

Decisions, decisions, decisions…

Before we started production, back in November 2010, we needed to get a few things straight; architecture, core values for the project, process and then getting everyone on-board with the decisions. We early on decided that we were going to learn all about CQRS, as it seemed to fit nicely with the requirements – especially for performance, and we were also requiring ourself that we wanted a rich domain model that really expressed all aspects of the system.  We also decided that we wanted to drive it all out applying BDD, and we wanted to be driving the project forward using Scrum and really be true to the process, not make our own version of Scrum. A dedicated product owner was assigned to the project that would have the responsibility for the backlog, make sure that we refined as needed, planned as needed and executed on it. 

Adding the business value

As I mentioned, this project came out of a technical need, not a concrete business need. We had the product owner role in place and he needed to fill the backlog with concrete business value. This was not an easy task to do, basically because the organization as a whole probably didn’t see the need for the project. In their defense, they had a perfectly fine solution today, not entirely optimal for smaller screens like a smartphone, but manageable. To the different store owners that normally provided the needs to the backlog, they were in desperate need of new features on existing solution, rather than this new thing targeting a platform they didn’t see much business value in adding. In combination with the fact that the organization had been in migration mode and all developer resources partly or close to full-time in periods being tied down to work related to migration of systems that was a result of merges and acquisitions, the organization had gotten used to not getting things done anyways. All this didn’t exactly create the most optimal environment for getting the real business value into the project. Something we really wanted. Early on we realized that the project could not be realized if we had user stories that were technical in nature. The first couple of months we did have quite a few technical user stories, and statistically these failed on estimation. We didn’t have any business value to relate them directly back to, and ended up in many cases as over-engineering and way out of their proportions as we as developers got creative and failed at doing our job; add business value. So we came to the conclusion; no technical user stories were allowed – ever. Something that I still today think was one of the wisest decisions we had on the project. It helped us get back and focus on why we were writing code every day; add business value. Even though this project was a spawn of the developers, there was clearly business value to guide us through. The approach became; lets pretend we’re writing an e-commerce solution for the first time. This turned out to be a good decision, it helped us  be naïve in our implementations – keeping in line with core principles of agile processes; the simplest thing that could possibly work. Our product owner was then left with the challenge of dragging the business value out of the business, he did a great job in doing that and at the same time getting them to realize the need for the change of platform that was in reality taking place. Something that became evident further down the line; we were in fact not building an e-commerce front-end for smartphones, but an entire new platform. More on that later.

YES, we did create a framework

One of the realizations we had early on was that we needed to standardize quite a few things. If you’re going to do that many new things and have a half-way chance of getting everyone with you and feel productive in the new environment, you need to get a basis working that people can work with. Back in 2008 I started a project called Bifrost, you can read more here. We looked at it and decided it was a good starting point for what we wanted to achieve. We also wanted the framework to be open-sourced. The philosophy was to create a generic framework to be the infrastructure sitting at the core of the application we were building. It would abstract away all the nitty gritty details of any underlying infrastructure, but also serve as the framework that promoted CQRS and the practices that we wanted. It was to be a framework that guided and assisted you, and very clearly not in your way. I’m not going to go in-depth in the framework, as there are more posts related to it specifically in the making and already out there.

CRUDing our way through CQRS

Well on our way, we had quite a few things we really couldn’t wrap our heads around. Coming from a very CRUD centric world, the thought of decoupling things in the way that CQRS was saying was really hard. And at the same time, there were potential for duplication in the code. I remember being completely freaked out at the beginning of the project. All my neural cells were screaming “NO! STOP!” – but we had to move on and get smarter, get passed the hurdles, learn. At first we really started making a mess out of things, just because we were building it on assumptions – the assumptions that CQRS is similar to doing regular old CRUD with what we used to know as a domain model. It was far from it, and we had a true eureka at one point were we realized something important; we were working hard an entire day on how to represent some queries in a good way so that they would be optimal in the code but also execute optimally – and it hit us as a ton of brick after leaving work that day. We were doing everything wrong, and we even came up with a mantra; “if a problem seems complicated, chances are we’re doing it wrong”. That was the turning point that helped us write code that was simpler, more testable, more focused, faster and we picked up pace in the project like I’ve never experienced before. 

From that point we had our mantra that really proved as a guiding star. Whenever we ran into things we didn’t have an answer to straight away and we started finding advanced solutions to the challenges, we applied the mantra and went back to rethink things.  

Tooling

Early in the project we realized we needed a tool for both visualizing the events being generated, but also be able to republish events. We came up with a tool built in Silverlight, using the pivot control from Microsoft to visualize.

Mimir

The real benefits

Looking back at what we did and trying to find the concrete benefits, I must say we now have gained serious amount of knowledge in a few areas. The thing that CQRS specifically gave us was the ability to model our domain properly. We achieved the separation we wanted between the behavior of the application and the things the behaviors caused changes to, the data on the other side. It helped us achieve greater flexibility, easier maintenance. Since we decided to not only just apply CQRS, but also build a reusable framework sitting at the bottom, we achieved a certain pattern of working that made things really easy to get started with development, and also a recognizable structure that made it easy to know were to put things if the core principles was explained to you.

I think by far the biggest benefit we achieved was the insight into how we should be developing software. Keeping things simple really have huge benefits. Decouple things, staying true to single-responsibility in every sense of the word single.

Another huge realization I had, something I have been saying all the time throughout my career but really got re-enforced with this project; concrete technology doesn’t really matter. Sure things will end up as a certain concrete technology – but stop thinking concretely when designing the system. Try to get down to the actual business needs, model it and let the concrete technology fall into place later. With this approach, you gain another useful possibility; doing top-down development. Start with the user interface, move your way down. Keep the feedback loop as tight as possible with the business. Don’t do more than is needed. This approach is something I know I will be missing the most in future projects. A tight feedback-loop is were the gold is hidden.

Were did we screw up?

This project must come across as a fairly peachy story. And sure, it was by far in my experience the project with the best code-base, the most structured one, the one that I personally learned the most from and also the one project in my career that we really managed to be on schedule and in fact for a couple of the releases we delivered more business value than was asked for. But it came at a price. One of the things we struggled with early on was to spread the knowledge across to the entire team and get everyone excited about the architecture, the new way of working with things and so forth. Personally I didn’t realize how invested people were in their existing solution, and also in the existing way of doing things. Me as the architect, should have seen this before we got started. The problem with not realizing this ended up being a growing problem in the group. You had a divide in the group of people buying into the entire story and those who didn’t or didn’t quite get the entire story. My theory is that we should have given the most invested members of the group a time for mourning. Get time to bury their friend through many years; the old project. We should have realized that we were in fact building for the future and would replace the existing solution at the beginning of the project and this should have been the official line. Instead it kind of organically became the official line. We did at the beginning do training in all the new techniques, and gave people time to learn. Basically didn’t give them any tasks for a few weeks and just pointed them in the general direction of things they should look at. What I think we failed on was that we didn’t point out that these things were not optional, these new ideas were in fact mandatory knowledge. We should have been much clearer about this and been vocal about the expectations. Another thing I think I would have done a bit different; involve more people in the framework part of things. With the risk of stepping on toes, I think it is not wrong of me to say that I was the framework guy. For the most part, I ended up working on the framework. Don’t get me wrong, I love doing that kind of work – but I think the experience, the design decisions got lost in translation and not everyone in the group understood why things were done as they were. 

Conclusion

The project and opportunity that was given to the team was awesome, I really appreciate the trust that was given to me for leading the way in this project. The pace we had, the stuff we did has so far amounted up to be the coolest project I’ve ever worked on – and I am happy to admit it; I miss the project. Hadn’t it been for a great opportunity that was given to me, I would have loved to stay on further. We had ups and downs, as with any software project, but overall I am wildly impressed with our accomplishments as a team and also by the end result.

Ohh… By the way. The end result can be found here.